1. Field of the Invention
The present invention is in the field of the production of sound recording, and more specifically relates to an improved method and apparatus for use in the process of producing master recordings.
2. The Prior Art
In a typical contemporary system for producing a master recording, the performance of the artists is recorded by a battery of microphones. The output of each microphone is recorded on an individual track by an audio tape recorder. The multi-track tape thus created forms a permanent storage for the performance, but the multi-track tape is unsuitable for use as a master recording.
A master recording is generated by playing the multi-track tape through a console whereby the signals in the various channels are mixed selectively enhanced or diminished, and filtered to obtain either a two-track tape representing the two channels conventionally used in stereo recordings or a four track tape currently coming into vogue. Clearly, any number of two-track tapes may be generated from the original multi-track tape. The master tape is then utilized to cut a master disc which, in turn, is used to create the stampers from which audio records are pressed.
The mixing and filtering process is, in the conventional technique, controlled by a human operator in accordance with his subjective determination of what constitutes the optimum equalizing, filtering and mixing. If the human operator is unsatisfied with the first two-track master tape produced, he may elect to vary the mixing and produce a second two-track master tape.
Generally, the mixing of the master tape is performed by a very skilled individual who controls the mixing in accordance with his personal judgment while listening to the master tape on extremely high quality monitoring equipment in the studio. This equipment generally includes large, high fidelity speakers and amplifiers. The resulting master tape preserves the sounds heard by the individual doing the mixing and is later transformed into an audio disc.
Unfortunately, most of the persons who will later listen to broadcasts of the audio records of the master tape will not have high quality, studio equipment at their disposal. Instead, the general public will be listening to an audio record as it is transmitted by a commercial transmitter to be received on a wide variety of relatively low quality radio receivers, equipped with low quality speakers.
Naturally, these listeners will not have the same performance that was mixed and recorded. The quality of the sound they hear, optimized for use with studio quality equipment loses something in the transmitting and receiving process. Commercial AM broadcast channels are limited by law to a relatively narrow bandwidth, and this necessarily results in some distortion of high frequency audio components. Further, most of the radios used by the general public have relatively small loudspeakers, resulting in some distortion of the low frequency audio components.
It has been found that a master tape optimized for studio quality equipment does not result in the best possible sound that can be achieved on the relatively low quality radio receivers used by the listening public.
On the contrary, it has been found that the master tape can be mixed in such a way that the quality of the sound heard by the listening public can be considerably improved.
This can be accomplished, according to the teaching of the present invention, by mixing the sounds recorded on the master tape in such a way as to compensate for the limitations of the relatively low quality radio receivers used by the public. This compensation can be achieved, according to the present invention, by stimulating, in the monitoring loop, the audible qualities of a broadcast transmitter and a receiver typically used by the public.